File indexing completed on 2024-05-19 04:00:11

 /*
     Underscore.js 1.9.1 <http://underscorejs.org>
 
     SPDX-FileCopyrightText: 2009-2018 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 
     SPDX-License-Identifier: MIT
 */
 
 (function() {
 
   // Baseline setup
   // --------------
 
   // Establish the root object, `window` (`self`) in the browser, `global`
   // on the server, or `this` in some virtual machines. We use `self`
   // instead of `window` for `WebWorker` support.
   var root = typeof self == 'object' && self.self === self && self ||
             typeof global == 'object' && global.global === global && global ||
             this ||
             {};
 
   // Save the previous value of the `_` variable.
   var previousUnderscore = root._;
 
   // Save bytes in the minified (but not gzipped) version:
   var ArrayProto = Array.prototype, ObjProto = Object.prototype;
   var SymbolProto = typeof Symbol !== 'undefined' ? Symbol.prototype : null;
 
   // Create quick reference variables for speed access to core prototypes.
   var push = ArrayProto.push,
       slice = ArrayProto.slice,
       toString = ObjProto.toString,
       hasOwnProperty = ObjProto.hasOwnProperty;
 
   // All **ECMAScript 5** native function implementations that we hope to use
   // are declared here.
   var nativeIsArray = Array.isArray,
       nativeKeys = Object.keys,
       nativeCreate = Object.create;
 
   // Naked function reference for surrogate-prototype-swapping.
   var Ctor = function(){};
 
   // Create a safe reference to the Underscore object for use below.
   var _ = function(obj) {
     if (obj instanceof _) return obj;
     if (!(this instanceof _)) return new _(obj);
     this._wrapped = obj;
   };
 
   // Export the Underscore object for **Node.js**, with
   // backwards-compatibility for their old module API. If we're in
   // the browser, add `_` as a global object.
   // (`nodeType` is checked to ensure that `module`
   // and `exports` are not HTML elements.)
   if (typeof exports != 'undefined' && !exports.nodeType) {
     if (typeof module != 'undefined' && !module.nodeType && module.exports) {
       exports = module.exports = _;
     }
     exports._ = _;
   } else {
     root._ = _;
   }
 
   // Current version.
   _.VERSION = '1.9.1';
 
   // Internal function that returns an efficient (for current engines) version
   // of the passed-in callback, to be repeatedly applied in other Underscore
   // functions.
   var optimizeCb = function(func, context, argCount) {
     if (context === void 0) return func;
     switch (argCount == null ? 3 : argCount) {
       case 1: return function(value) {
         return func.call(context, value);
       };
       // The 2-argument case is omitted because we’re not using it.
       case 3: return function(value, index, collection) {
         return func.call(context, value, index, collection);
       };
       case 4: return function(accumulator, value, index, collection) {
         return func.call(context, accumulator, value, index, collection);
       };
     }
     return function() {
       return func.apply(context, arguments);
     };
   };
 
   var builtinIteratee;
 
   // An internal function to generate callbacks that can be applied to each
   // element in a collection, returning the desired result — either `identity`,
   // an arbitrary callback, a property matcher, or a property accessor.
   var cb = function(value, context, argCount) {
     if (_.iteratee !== builtinIteratee) return _.iteratee(value, context);
     if (value == null) return _.identity;
     if (_.isFunction(value)) return optimizeCb(value, context, argCount);
     if (_.isObject(value) && !_.isArray(value)) return _.matcher(value);
     return _.property(value);
   };
 
   // External wrapper for our callback generator. Users may customize
   // `_.iteratee` if they want additional predicate/iteratee shorthand styles.
   // This abstraction hides the internal-only argCount argument.
   _.iteratee = builtinIteratee = function(value, context) {
     return cb(value, context, Infinity);
   };
 
   // Some functions take a variable number of arguments, or a few expected
   // arguments at the beginning and then a variable number of values to operate
   // on. This helper accumulates all remaining arguments past the function’s
   // argument length (or an explicit `startIndex`), into an array that becomes
   // the last argument. Similar to ES6’s "rest parameter".
   var restArguments = function(func, startIndex) {
     startIndex = startIndex == null ? func.length - 1 : +startIndex;
     return function() {
       var length = Math.max(arguments.length - startIndex, 0),
           rest = Array(length),
           index = 0;
       for (; index < length; index++) {
         rest[index] = arguments[index + startIndex];
       }
       switch (startIndex) {
         case 0: return func.call(this, rest);
         case 1: return func.call(this, arguments[0], rest);
         case 2: return func.call(this, arguments[0], arguments[1], rest);
       }
       var args = Array(startIndex + 1);
       for (index = 0; index < startIndex; index++) {
         args[index] = arguments[index];
       }
       args[startIndex] = rest;
       return func.apply(this, args);
     };
   };
 
   // An internal function for creating a new object that inherits from another.
   var baseCreate = function(prototype) {
     if (!_.isObject(prototype)) return {};
     if (nativeCreate) return nativeCreate(prototype);
     Ctor.prototype = prototype;
     var result = new Ctor;
     Ctor.prototype = null;
     return result;
   };
 
   var shallowProperty = function(key) {
     return function(obj) {
       return obj == null ? void 0 : obj[key];
     };
   };
 
   var has = function(obj, path) {
     return obj != null && hasOwnProperty.call(obj, path);
   }
 
   var deepGet = function(obj, path) {
     var length = path.length;
     for (var i = 0; i < length; i++) {
       if (obj == null) return void 0;
       obj = obj[path[i]];
     }
     return length ? obj : void 0;
   };
 
   // Helper for collection methods to determine whether a collection
   // should be iterated as an array or as an object.
   // Related: http://people.mozilla.org/~jorendorff/es6-draft.html#sec-tolength
   // Avoids a very nasty iOS 8 JIT bug on ARM-64. #2094
   var MAX_ARRAY_INDEX = Math.pow(2, 53) - 1;
   var getLength = shallowProperty('length');
   var isArrayLike = function(collection) {
     var length = getLength(collection);
     return typeof length == 'number' && length >= 0 && length <= MAX_ARRAY_INDEX;
   };
 
   // Collection Functions
   // --------------------
 
   // The cornerstone, an `each` implementation, aka `forEach`.
   // Handles raw objects in addition to array-likes. Treats all
   // sparse array-likes as if they were dense.
   _.each = _.forEach = function(obj, iteratee, context) {
     iteratee = optimizeCb(iteratee, context);
     var i, length;
     if (isArrayLike(obj)) {
       for (i = 0, length = obj.length; i < length; i++) {
         iteratee(obj[i], i, obj);
       }
     } else {
       var keys = _.keys(obj);
       for (i = 0, length = keys.length; i < length; i++) {
         iteratee(obj[keys[i]], keys[i], obj);
       }
     }
     return obj;
   };
 
   // Return the results of applying the iteratee to each element.
   _.map = _.collect = function(obj, iteratee, context) {
     iteratee = cb(iteratee, context);
     var keys = !isArrayLike(obj) && _.keys(obj),
         length = (keys || obj).length,
         results = Array(length);
     for (var index = 0; index < length; index++) {
       var currentKey = keys ? keys[index] : index;
       results[index] = iteratee(obj[currentKey], currentKey, obj);
     }
     return results;
   };
 
   // Create a reducing function iterating left or right.
   var createReduce = function(dir) {
     // Wrap code that reassigns argument variables in a separate function than
     // the one that accesses `arguments.length` to avoid a perf hit. (#1991)
     var reducer = function(obj, iteratee, memo, initial) {
       var keys = !isArrayLike(obj) && _.keys(obj),
           length = (keys || obj).length,
           index = dir > 0 ? 0 : length - 1;
       if (!initial) {
         memo = obj[keys ? keys[index] : index];
         index += dir;
       }
       for (; index >= 0 && index < length; index += dir) {
         var currentKey = keys ? keys[index] : index;
         memo = iteratee(memo, obj[currentKey], currentKey, obj);
       }
       return memo;
     };
 
     return function(obj, iteratee, memo, context) {
       var initial = arguments.length >= 3;
       return reducer(obj, optimizeCb(iteratee, context, 4), memo, initial);
     };
   };
 
   // **Reduce** builds up a single result from a list of values, aka `inject`,
   // or `foldl`.
   _.reduce = _.foldl = _.inject = createReduce(1);
 
   // The right-associative version of reduce, also known as `foldr`.
   _.reduceRight = _.foldr = createReduce(-1);
 
   // Return the first value which passes a truth test. Aliased as `detect`.
   _.find = _.detect = function(obj, predicate, context) {
     var keyFinder = isArrayLike(obj) ? _.findIndex : _.findKey;
     var key = keyFinder(obj, predicate, context);
     if (key !== void 0 && key !== -1) return obj[key];
   };
 
   // Return all the elements that pass a truth test.
   // Aliased as `select`.
   _.filter = _.select = function(obj, predicate, context) {
     var results = [];
     predicate = cb(predicate, context);
     _.each(obj, function(value, index, list) {
       if (predicate(value, index, list)) results.push(value);
     });
     return results;
   };
 
   // Return all the elements for which a truth test fails.
   _.reject = function(obj, predicate, context) {
     return _.filter(obj, _.negate(cb(predicate)), context);
   };
 
   // Determine whether all of the elements match a truth test.
   // Aliased as `all`.
   _.every = _.all = function(obj, predicate, context) {
     predicate = cb(predicate, context);
     var keys = !isArrayLike(obj) && _.keys(obj),
         length = (keys || obj).length;
     for (var index = 0; index < length; index++) {
       var currentKey = keys ? keys[index] : index;
       if (!predicate(obj[currentKey], currentKey, obj)) return false;
     }
     return true;
   };
 
   // Determine if at least one element in the object matches a truth test.
   // Aliased as `any`.
   _.some = _.any = function(obj, predicate, context) {
     predicate = cb(predicate, context);
     var keys = !isArrayLike(obj) && _.keys(obj),
         length = (keys || obj).length;
     for (var index = 0; index < length; index++) {
       var currentKey = keys ? keys[index] : index;
       if (predicate(obj[currentKey], currentKey, obj)) return true;
     }
     return false;
   };
 
   // Determine if the array or object contains a given item (using `===`).
   // Aliased as `includes` and `include`.
   _.contains = _.includes = _.include = function(obj, item, fromIndex, guard) {
     if (!isArrayLike(obj)) obj = _.values(obj);
     if (typeof fromIndex != 'number' || guard) fromIndex = 0;
     return _.indexOf(obj, item, fromIndex) >= 0;
   };
 
   // Invoke a method (with arguments) on every item in a collection.
   _.invoke = restArguments(function(obj, path, args) {
     var contextPath, func;
     if (_.isFunction(path)) {
       func = path;
     } else if (_.isArray(path)) {
       contextPath = path.slice(0, -1);
       path = path[path.length - 1];
     }
     return _.map(obj, function(context) {
       var method = func;
       if (!method) {
         if (contextPath && contextPath.length) {
           context = deepGet(context, contextPath);
         }
         if (context == null) return void 0;
         method = context[path];
       }
       return method == null ? method : method.apply(context, args);
     });
   });
 
   // Convenience version of a common use case of `map`: fetching a property.
   _.pluck = function(obj, key) {
     return _.map(obj, _.property(key));
   };
 
   // Convenience version of a common use case of `filter`: selecting only objects
   // containing specific `key:value` pairs.
   _.where = function(obj, attrs) {
     return _.filter(obj, _.matcher(attrs));
   };
 
   // Convenience version of a common use case of `find`: getting the first object
   // containing specific `key:value` pairs.
   _.findWhere = function(obj, attrs) {
     return _.find(obj, _.matcher(attrs));
   };
 
   // Return the maximum element (or element-based computation).
   _.max = function(obj, iteratee, context) {
     var result = -Infinity, lastComputed = -Infinity,
         value, computed;
     if (iteratee == null || typeof iteratee == 'number' && typeof obj[0] != 'object' && obj != null) {
       obj = isArrayLike(obj) ? obj : _.values(obj);
       for (var i = 0, length = obj.length; i < length; i++) {
         value = obj[i];
         if (value != null && value > result) {
           result = value;
         }
       }
     } else {
       iteratee = cb(iteratee, context);
       _.each(obj, function(v, index, list) {
         computed = iteratee(v, index, list);
         if (computed > lastComputed || computed === -Infinity && result === -Infinity) {
           result = v;
           lastComputed = computed;
         }
       });
     }
     return result;
   };
 
   // Return the minimum element (or element-based computation).
   _.min = function(obj, iteratee, context) {
     var result = Infinity, lastComputed = Infinity,
         value, computed;
     if (iteratee == null || typeof iteratee == 'number' && typeof obj[0] != 'object' && obj != null) {
       obj = isArrayLike(obj) ? obj : _.values(obj);
       for (var i = 0, length = obj.length; i < length; i++) {
         value = obj[i];
         if (value != null && value < result) {
           result = value;
         }
       }
     } else {
       iteratee = cb(iteratee, context);
       _.each(obj, function(v, index, list) {
         computed = iteratee(v, index, list);
         if (computed < lastComputed || computed === Infinity && result === Infinity) {
           result = v;
           lastComputed = computed;
         }
       });
     }
     return result;
   };
 
   // Shuffle a collection.
   _.shuffle = function(obj) {
     return _.sample(obj, Infinity);
   };
 
   // Sample **n** random values from a collection using the modern version of the
   // [Fisher-Yates shuffle](http://en.wikipedia.org/wiki/Fisher–Yates_shuffle).
   // If **n** is not specified, returns a single random element.
   // The internal `guard` argument allows it to work with `map`.
   _.sample = function(obj, n, guard) {
     if (n == null || guard) {
       if (!isArrayLike(obj)) obj = _.values(obj);
       return obj[_.random(obj.length - 1)];
     }
     var sample = isArrayLike(obj) ? _.clone(obj) : _.values(obj);
     var length = getLength(sample);
     n = Math.max(Math.min(n, length), 0);
     var last = length - 1;
     for (var index = 0; index < n; index++) {
       var rand = _.random(index, last);
       var temp = sample[index];
       sample[index] = sample[rand];
       sample[rand] = temp;
     }
     return sample.slice(0, n);
   };
 
   // Sort the object's values by a criterion produced by an iteratee.
   _.sortBy = function(obj, iteratee, context) {
     var index = 0;
     iteratee = cb(iteratee, context);
     return _.pluck(_.map(obj, function(value, key, list) {
       return {
         value: value,
         index: index++,
         criteria: iteratee(value, key, list)
       };
     }).sort(function(left, right) {
       var a = left.criteria;
       var b = right.criteria;
       if (a !== b) {
         if (a > b || a === void 0) return 1;
         if (a < b || b === void 0) return -1;
       }
       return left.index - right.index;
     }), 'value');
   };
 
   // An internal function used for aggregate "group by" operations.
   var group = function(behavior, partition) {
     return function(obj, iteratee, context) {
       var result = partition ? [[], []] : {};
       iteratee = cb(iteratee, context);
       _.each(obj, function(value, index) {
         var key = iteratee(value, index, obj);
         behavior(result, value, key);
       });
       return result;
     };
   };
 
   // Groups the object's values by a criterion. Pass either a string attribute
   // to group by, or a function that returns the criterion.
   _.groupBy = group(function(result, value, key) {
     if (has(result, key)) result[key].push(value); else result[key] = [value];
   });
 
   // Indexes the object's values by a criterion, similar to `groupBy`, but for
   // when you know that your index values will be unique.
   _.indexBy = group(function(result, value, key) {
     result[key] = value;
   });
 
   // Counts instances of an object that group by a certain criterion. Pass
   // either a string attribute to count by, or a function that returns the
   // criterion.
   _.countBy = group(function(result, value, key) {
     if (has(result, key)) result[key]++; else result[key] = 1;
   });
 
   var reStrSymbol = /[^\ud800-\udfff]|[\ud800-\udbff][\udc00-\udfff]|[\ud800-\udfff]/g;
   // Safely create a real, live array from anything iterable.
   _.toArray = function(obj) {
     if (!obj) return [];
     if (_.isArray(obj)) return slice.call(obj);
     if (_.isString(obj)) {
       // Keep surrogate pair characters together
       return obj.match(reStrSymbol);
     }
     if (isArrayLike(obj)) return _.map(obj, _.identity);
     return _.values(obj);
   };
 
   // Return the number of elements in an object.
   _.size = function(obj) {
     if (obj == null) return 0;
     return isArrayLike(obj) ? obj.length : _.keys(obj).length;
   };
 
   // Split a collection into two arrays: one whose elements all satisfy the given
   // predicate, and one whose elements all do not satisfy the predicate.
   _.partition = group(function(result, value, pass) {
     result[pass ? 0 : 1].push(value);
   }, true);
 
   // Array Functions
   // ---------------
 
   // Get the first element of an array. Passing **n** will return the first N
   // values in the array. Aliased as `head` and `take`. The **guard** check
   // allows it to work with `_.map`.
   _.first = _.head = _.take = function(array, n, guard) {
     if (array == null || array.length < 1) return n == null ? void 0 : [];
     if (n == null || guard) return array[0];
     return _.initial(array, array.length - n);
   };
 
   // Returns everything but the last entry of the array. Especially useful on
   // the arguments object. Passing **n** will return all the values in
   // the array, excluding the last N.
   _.initial = function(array, n, guard) {
     return slice.call(array, 0, Math.max(0, array.length - (n == null || guard ? 1 : n)));
   };
 
   // Get the last element of an array. Passing **n** will return the last N
   // values in the array.
   _.last = function(array, n, guard) {
     if (array == null || array.length < 1) return n == null ? void 0 : [];
     if (n == null || guard) return array[array.length - 1];
     return _.rest(array, Math.max(0, array.length - n));
   };
 
   // Returns everything but the first entry of the array. Aliased as `tail` and `drop`.
   // Especially useful on the arguments object. Passing an **n** will return
   // the rest N values in the array.
   _.rest = _.tail = _.drop = function(array, n, guard) {
     return slice.call(array, n == null || guard ? 1 : n);
   };
 
   // Trim out all falsy values from an array.
   _.compact = function(array) {
     return _.filter(array, Boolean);
   };
 
   // Internal implementation of a recursive `flatten` function.
   var flatten = function(input, shallow, strict, output) {
     output = output || [];
     var idx = output.length;
     for (var i = 0, length = getLength(input); i < length; i++) {
       var value = input[i];
       if (isArrayLike(value) && (_.isArray(value) || _.isArguments(value))) {
         // Flatten current level of array or arguments object.
         if (shallow) {
           var j = 0, len = value.length;
           while (j < len) output[idx++] = value[j++];
         } else {
           flatten(value, shallow, strict, output);
           idx = output.length;
         }
       } else if (!strict) {
         output[idx++] = value;
       }
     }
     return output;
   };
 
   // Flatten out an array, either recursively (by default), or just one level.
   _.flatten = function(array, shallow) {
     return flatten(array, shallow, false);
   };
 
   // Return a version of the array that does not contain the specified value(s).
   _.without = restArguments(function(array, otherArrays) {
     return _.difference(array, otherArrays);
   });
 
   // Produce a duplicate-free version of the array. If the array has already
   // been sorted, you have the option of using a faster algorithm.
   // The faster algorithm will not work with an iteratee if the iteratee
   // is not a one-to-one function, so providing an iteratee will disable
   // the faster algorithm.
   // Aliased as `unique`.
   _.uniq = _.unique = function(array, isSorted, iteratee, context) {
     if (!_.isBoolean(isSorted)) {
       context = iteratee;
       iteratee = isSorted;
       isSorted = false;
     }
     if (iteratee != null) iteratee = cb(iteratee, context);
     var result = [];
     var seen = [];
     for (var i = 0, length = getLength(array); i < length; i++) {
       var value = array[i],
           computed = iteratee ? iteratee(value, i, array) : value;
       if (isSorted && !iteratee) {
         if (!i || seen !== computed) result.push(value);
         seen = computed;
       } else if (iteratee) {
         if (!_.contains(seen, computed)) {
           seen.push(computed);
           result.push(value);
         }
       } else if (!_.contains(result, value)) {
         result.push(value);
       }
     }
     return result;
   };
 
   // Produce an array that contains the union: each distinct element from all of
   // the passed-in arrays.
   _.union = restArguments(function(arrays) {
     return _.uniq(flatten(arrays, true, true));
   });
 
   // Produce an array that contains every item shared between all the
   // passed-in arrays.
   _.intersection = function(array) {
     var result = [];
     var argsLength = arguments.length;
     for (var i = 0, length = getLength(array); i < length; i++) {
       var item = array[i];
       if (_.contains(result, item)) continue;
       var j;
       for (j = 1; j < argsLength; j++) {
         if (!_.contains(arguments[j], item)) break;
       }
       if (j === argsLength) result.push(item);
     }
     return result;
   };
 
   // Take the difference between one array and a number of other arrays.
   // Only the elements present in just the first array will remain.
   _.difference = restArguments(function(array, rest) {
     rest = flatten(rest, true, true);
     return _.filter(array, function(value){
       return !_.contains(rest, value);
     });
   });
 
   // Complement of _.zip. Unzip accepts an array of arrays and groups
   // each array's elements on shared indices.
   _.unzip = function(array) {
     var length = array && _.max(array, getLength).length || 0;
     var result = Array(length);
 
     for (var index = 0; index < length; index++) {
       result[index] = _.pluck(array, index);
     }
     return result;
   };
 
   // Zip together multiple lists into a single array -- elements that share
   // an index go together.
   _.zip = restArguments(_.unzip);
 
   // Converts lists into objects. Pass either a single array of `[key, value]`
   // pairs, or two parallel arrays of the same length -- one of keys, and one of
   // the corresponding values. Passing by pairs is the reverse of _.pairs.
   _.object = function(list, values) {
     var result = {};
     for (var i = 0, length = getLength(list); i < length; i++) {
       if (values) {
         result[list[i]] = values[i];
       } else {
         result[list[i][0]] = list[i][1];
       }
     }
     return result;
   };
 
   // Generator function to create the findIndex and findLastIndex functions.
   var createPredicateIndexFinder = function(dir) {
     return function(array, predicate, context) {
       predicate = cb(predicate, context);
       var length = getLength(array);
       var index = dir > 0 ? 0 : length - 1;
       for (; index >= 0 && index < length; index += dir) {
         if (predicate(array[index], index, array)) return index;
       }
       return -1;
     };
   };
 
   // Returns the first index on an array-like that passes a predicate test.
   _.findIndex = createPredicateIndexFinder(1);
   _.findLastIndex = createPredicateIndexFinder(-1);
 
   // Use a comparator function to figure out the smallest index at which
   // an object should be inserted so as to maintain order. Uses binary search.
   _.sortedIndex = function(array, obj, iteratee, context) {
     iteratee = cb(iteratee, context, 1);
     var value = iteratee(obj);
     var low = 0, high = getLength(array);
     while (low < high) {
       var mid = Math.floor((low + high) / 2);
       if (iteratee(array[mid]) < value) low = mid + 1; else high = mid;
     }
     return low;
   };
 
   // Generator function to create the indexOf and lastIndexOf functions.
   var createIndexFinder = function(dir, predicateFind, sortedIndex) {
     return function(array, item, idx) {
       var i = 0, length = getLength(array);
       if (typeof idx == 'number') {
         if (dir > 0) {
           i = idx >= 0 ? idx : Math.max(idx + length, i);
         } else {
           length = idx >= 0 ? Math.min(idx + 1, length) : idx + length + 1;
         }
       } else if (sortedIndex && idx && length) {
         idx = sortedIndex(array, item);
         return array[idx] === item ? idx : -1;
       }
       if (item !== item) {
         idx = predicateFind(slice.call(array, i, length), _.isNaN);
         return idx >= 0 ? idx + i : -1;
       }
       for (idx = dir > 0 ? i : length - 1; idx >= 0 && idx < length; idx += dir) {
         if (array[idx] === item) return idx;
       }
       return -1;
     };
   };
 
   // Return the position of the first occurrence of an item in an array,
   // or -1 if the item is not included in the array.
   // If the array is large and already in sort order, pass `true`
   // for **isSorted** to use binary search.
   _.indexOf = createIndexFinder(1, _.findIndex, _.sortedIndex);
   _.lastIndexOf = createIndexFinder(-1, _.findLastIndex);
 
   // Generate an integer Array containing an arithmetic progression. A port of
   // the native Python `range()` function. See
   // [the Python documentation](http://docs.python.org/library/functions.html#range).
   _.range = function(start, stop, step) {
     if (stop == null) {
       stop = start || 0;
       start = 0;
     }
     if (!step) {
       step = stop < start ? -1 : 1;
     }
 
     var length = Math.max(Math.ceil((stop - start) / step), 0);
     var range = Array(length);
 
     for (var idx = 0; idx < length; idx++, start += step) {
       range[idx] = start;
     }
 
     return range;
   };
 
   // Chunk a single array into multiple arrays, each containing `count` or fewer
   // items.
   _.chunk = function(array, count) {
     if (count == null || count < 1) return [];
     var result = [];
     var i = 0, length = array.length;
     while (i < length) {
       result.push(slice.call(array, i, i += count));
     }
     return result;
   };
 
   // Function (ahem) Functions
   // ------------------
 
   // Determines whether to execute a function as a constructor
   // or a normal function with the provided arguments.
   var executeBound = function(sourceFunc, boundFunc, context, callingContext, args) {
     if (!(callingContext instanceof boundFunc)) return sourceFunc.apply(context, args);
     var self = baseCreate(sourceFunc.prototype);
     var result = sourceFunc.apply(self, args);
     if (_.isObject(result)) return result;
     return self;
   };
 
   // Create a function bound to a given object (assigning `this`, and arguments,
   // optionally). Delegates to **ECMAScript 5**'s native `Function.bind` if
   // available.
   _.bind = restArguments(function(func, context, args) {
     if (!_.isFunction(func)) throw new TypeError('Bind must be called on a function');
     var bound = restArguments(function(callArgs) {
       return executeBound(func, bound, context, this, args.concat(callArgs));
     });
     return bound;
   });
 
   // Partially apply a function by creating a version that has had some of its
   // arguments pre-filled, without changing its dynamic `this` context. _ acts
   // as a placeholder by default, allowing any combination of arguments to be
   // pre-filled. Set `_.partial.placeholder` for a custom placeholder argument.
   _.partial = restArguments(function(func, boundArgs) {
     var placeholder = _.partial.placeholder;
     var bound = function() {
       var position = 0, length = boundArgs.length;
       var args = Array(length);
       for (var i = 0; i < length; i++) {
         args[i] = boundArgs[i] === placeholder ? arguments[position++] : boundArgs[i];
       }
       while (position < arguments.length) args.push(arguments[position++]);
       return executeBound(func, bound, this, this, args);
     };
     return bound;
   });
 
   _.partial.placeholder = _;
 
   // Bind a number of an object's methods to that object. Remaining arguments
   // are the method names to be bound. Useful for ensuring that all callbacks
   // defined on an object belong to it.
   _.bindAll = restArguments(function(obj, keys) {
     keys = flatten(keys, false, false);
     var index = keys.length;
     if (index < 1) throw new Error('bindAll must be passed function names');
     while (index--) {
       var key = keys[index];
       obj[key] = _.bind(obj[key], obj);
     }
   });
 
   // Memoize an expensive function by storing its results.
   _.memoize = function(func, hasher) {
     var memoize = function(key) {
       var cache = memoize.cache;
       var address = '' + (hasher ? hasher.apply(this, arguments) : key);
       if (!has(cache, address)) cache[address] = func.apply(this, arguments);
       return cache[address];
     };
     memoize.cache = {};
     return memoize;
   };
 
   // Delays a function for the given number of milliseconds, and then calls
   // it with the arguments supplied.
   _.delay = restArguments(function(func, wait, args) {
     return setTimeout(function() {
       return func.apply(null, args);
     }, wait);
   });
 
   // Defers a function, scheduling it to run after the current call stack has
   // cleared.
   _.defer = _.partial(_.delay, _, 1);
 
   // Returns a function, that, when invoked, will only be triggered at most once
   // during a given window of time. Normally, the throttled function will run
   // as much as it can, without ever going more than once per `wait` duration;
   // but if you'd like to disable the execution on the leading edge, pass
   // `{leading: false}`. To disable execution on the trailing edge, ditto.
   _.throttle = function(func, wait, options) {
     var timeout, context, args, result;
     var previous = 0;
     if (!options) options = {};
 
     var later = function() {
       previous = options.leading === false ? 0 : _.now();
       timeout = null;
       result = func.apply(context, args);
       if (!timeout) context = args = null;
     };
 
     var throttled = function() {
       var now = _.now();
       if (!previous && options.leading === false) previous = now;
       var remaining = wait - (now - previous);
       context = this;
       args = arguments;
       if (remaining <= 0 || remaining > wait) {
         if (timeout) {
           clearTimeout(timeout);
           timeout = null;
         }
         previous = now;
         result = func.apply(context, args);
         if (!timeout) context = args = null;
       } else if (!timeout && options.trailing !== false) {
         timeout = setTimeout(later, remaining);
       }
       return result;
     };
 
     throttled.cancel = function() {
       clearTimeout(timeout);
       previous = 0;
       timeout = context = args = null;
     };
 
     return throttled;
   };
 
   // Returns a function, that, as long as it continues to be invoked, will not
   // be triggered. The function will be called after it stops being called for
   // N milliseconds. If `immediate` is passed, trigger the function on the
   // leading edge, instead of the trailing.
   _.debounce = function(func, wait, immediate) {
     var timeout, result;
 
     var later = function(context, args) {
       timeout = null;
       if (args) result = func.apply(context, args);
     };
 
     var debounced = restArguments(function(args) {
       if (timeout) clearTimeout(timeout);
       if (immediate) {
         var callNow = !timeout;
         timeout = setTimeout(later, wait);
         if (callNow) result = func.apply(this, args);
       } else {
         timeout = _.delay(later, wait, this, args);
       }
 
       return result;
     });
 
     debounced.cancel = function() {
       clearTimeout(timeout);
       timeout = null;
     };
 
     return debounced;
   };
 
   // Returns the first function passed as an argument to the second,
   // allowing you to adjust arguments, run code before and after, and
   // conditionally execute the original function.
   _.wrap = function(func, wrapper) {
     return _.partial(wrapper, func);
   };
 
   // Returns a negated version of the passed-in predicate.
   _.negate = function(predicate) {
     return function() {
       return !predicate.apply(this, arguments);
     };
   };
 
   // Returns a function that is the composition of a list of functions, each
   // consuming the return value of the function that follows.
   _.compose = function() {
     var args = arguments;
     var start = args.length - 1;
     return function() {
       var i = start;
       var result = args[start].apply(this, arguments);
       while (i--) result = args[i].call(this, result);
       return result;
     };
   };
 
   // Returns a function that will only be executed on and after the Nth call.
   _.after = function(times, func) {
     return function() {
       if (--times < 1) {
         return func.apply(this, arguments);
       }
     };
   };
 
   // Returns a function that will only be executed up to (but not including) the Nth call.
   _.before = function(times, func) {
     var memo;
     return function() {
       if (--times > 0) {
         memo = func.apply(this, arguments);
       }
       if (times <= 1) func = null;
       return memo;
     };
   };
 
   // Returns a function that will be executed at most one time, no matter how
   // often you call it. Useful for lazy initialization.
   _.once = _.partial(_.before, 2);
 
   _.restArguments = restArguments;
 
   // Object Functions
   // ----------------
 
   // Keys in IE < 9 that won't be iterated by `for key in ...` and thus missed.
   var hasEnumBug = !{toString: null}.propertyIsEnumerable('toString');
   var nonEnumerableProps = ['valueOf', 'isPrototypeOf', 'toString',
     'propertyIsEnumerable', 'hasOwnProperty', 'toLocaleString'];
 
   var collectNonEnumProps = function(obj, keys) {
     var nonEnumIdx = nonEnumerableProps.length;
     var constructor = obj.constructor;
     var proto = _.isFunction(constructor) && constructor.prototype || ObjProto;
 
     // Constructor is a special case.
     var prop = 'constructor';
     if (has(obj, prop) && !_.contains(keys, prop)) keys.push(prop);
 
     while (nonEnumIdx--) {
       prop = nonEnumerableProps[nonEnumIdx];
       if (prop in obj && obj[prop] !== proto[prop] && !_.contains(keys, prop)) {
         keys.push(prop);
       }
     }
   };
 
   // Retrieve the names of an object's own properties.
   // Delegates to **ECMAScript 5**'s native `Object.keys`.
   _.keys = function(obj) {
     if (!_.isObject(obj)) return [];
     if (nativeKeys) return nativeKeys(obj);
     var keys = [];
     for (var key in obj) if (has(obj, key)) keys.push(key);
     // Ahem, IE < 9.
     if (hasEnumBug) collectNonEnumProps(obj, keys);
     return keys;
   };
 
   // Retrieve all the property names of an object.
   _.allKeys = function(obj) {
     if (!_.isObject(obj)) return [];
     var keys = [];
     for (var key in obj) keys.push(key);
     // Ahem, IE < 9.
     if (hasEnumBug) collectNonEnumProps(obj, keys);
     return keys;
   };
 
   // Retrieve the values of an object's properties.
   _.values = function(obj) {
     var keys = _.keys(obj);
     var length = keys.length;
     var values = Array(length);
     for (var i = 0; i < length; i++) {
       values[i] = obj[keys[i]];
     }
     return values;
   };
 
   // Returns the results of applying the iteratee to each element of the object.
   // In contrast to _.map it returns an object.
   _.mapObject = function(obj, iteratee, context) {
     iteratee = cb(iteratee, context);
     var keys = _.keys(obj),
         length = keys.length,
         results = {};
     for (var index = 0; index < length; index++) {
       var currentKey = keys[index];
       results[currentKey] = iteratee(obj[currentKey], currentKey, obj);
     }
     return results;
   };
 
   // Convert an object into a list of `[key, value]` pairs.
   // The opposite of _.object.
   _.pairs = function(obj) {
     var keys = _.keys(obj);
     var length = keys.length;
     var pairs = Array(length);
     for (var i = 0; i < length; i++) {
       pairs[i] = [keys[i], obj[keys[i]]];
     }
     return pairs;
   };
 
   // Invert the keys and values of an object. The values must be serializable.
   _.invert = function(obj) {
     var result = {};
     var keys = _.keys(obj);
     for (var i = 0, length = keys.length; i < length; i++) {
       result[obj[keys[i]]] = keys[i];
     }
     return result;
   };
 
   // Return a sorted list of the function names available on the object.
   // Aliased as `methods`.
   _.functions = _.methods = function(obj) {
     var names = [];
     for (var key in obj) {
       if (_.isFunction(obj[key])) names.push(key);
     }
     return names.sort();
   };
 
   // An internal function for creating assigner functions.
   var createAssigner = function(keysFunc, defaults) {
     return function(obj) {
       var length = arguments.length;
       if (defaults) obj = Object(obj);
       if (length < 2 || obj == null) return obj;
       for (var index = 1; index < length; index++) {
         var source = arguments[index],
             keys = keysFunc(source),
             l = keys.length;
         for (var i = 0; i < l; i++) {
           var key = keys[i];
           if (!defaults || obj[key] === void 0) obj[key] = source[key];
         }
       }
       return obj;
     };
   };
 
   // Extend a given object with all the properties in passed-in object(s).
   _.extend = createAssigner(_.allKeys);
 
   // Assigns a given object with all the own properties in the passed-in object(s).
   // (https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object/assign)
   _.extendOwn = _.assign = createAssigner(_.keys);
 
   // Returns the first key on an object that passes a predicate test.
   _.findKey = function(obj, predicate, context) {
     predicate = cb(predicate, context);
     var keys = _.keys(obj), key;
     for (var i = 0, length = keys.length; i < length; i++) {
       key = keys[i];
       if (predicate(obj[key], key, obj)) return key;
     }
   };
 
   // Internal pick helper function to determine if `obj` has key `key`.
   var keyInObj = function(value, key, obj) {
     return key in obj;
   };
 
   // Return a copy of the object only containing the whitelisted properties.
   _.pick = restArguments(function(obj, keys) {
     var result = {}, iteratee = keys[0];
     if (obj == null) return result;
     if (_.isFunction(iteratee)) {
       if (keys.length > 1) iteratee = optimizeCb(iteratee, keys[1]);
       keys = _.allKeys(obj);
     } else {
       iteratee = keyInObj;
       keys = flatten(keys, false, false);
       obj = Object(obj);
     }
     for (var i = 0, length = keys.length; i < length; i++) {
       var key = keys[i];
       var value = obj[key];
       if (iteratee(value, key, obj)) result[key] = value;
     }
     return result;
   });
 
   // Return a copy of the object without the blacklisted properties.
   _.omit = restArguments(function(obj, keys) {
     var iteratee = keys[0], context;
     if (_.isFunction(iteratee)) {
       iteratee = _.negate(iteratee);
       if (keys.length > 1) context = keys[1];
     } else {
       keys = _.map(flatten(keys, false, false), String);
       iteratee = function(value, key) {
         return !_.contains(keys, key);
       };
     }
     return _.pick(obj, iteratee, context);
   });
 
   // Fill in a given object with default properties.
   _.defaults = createAssigner(_.allKeys, true);
 
   // Creates an object that inherits from the given prototype object.
   // If additional properties are provided then they will be added to the
   // created object.
   _.create = function(prototype, props) {
     var result = baseCreate(prototype);
     if (props) _.extendOwn(result, props);
     return result;
   };
 
   // Create a (shallow-cloned) duplicate of an object.
   _.clone = function(obj) {
     if (!_.isObject(obj)) return obj;
     return _.isArray(obj) ? obj.slice() : _.extend({}, obj);
   };
 
   // Invokes interceptor with the obj, and then returns obj.
   // The primary purpose of this method is to "tap into" a method chain, in
   // order to perform operations on intermediate results within the chain.
   _.tap = function(obj, interceptor) {
     interceptor(obj);
     return obj;
   };
 
   // Returns whether an object has a given set of `key:value` pairs.
   _.isMatch = function(object, attrs) {
     var keys = _.keys(attrs), length = keys.length;
     if (object == null) return !length;
     var obj = Object(object);
     for (var i = 0; i < length; i++) {
       var key = keys[i];
       if (attrs[key] !== obj[key] || !(key in obj)) return false;
     }
     return true;
   };
 
 
   // Internal recursive comparison function for `isEqual`.
   var eq, deepEq;
   eq = function(a, b, aStack, bStack) {
     // Identical objects are equal. `0 === -0`, but they aren't identical.
     // See the [Harmony `egal` proposal](http://wiki.ecmascript.org/doku.php?id=harmony:egal).
     if (a === b) return a !== 0 || 1 / a === 1 / b;
     // `null` or `undefined` only equal to itself (strict comparison).
     if (a == null || b == null) return false;
     // `NaN`s are equivalent, but non-reflexive.
     if (a !== a) return b !== b;
     // Exhaust primitive checks
     var type = typeof a;
     if (type !== 'function' && type !== 'object' && typeof b != 'object') return false;
     return deepEq(a, b, aStack, bStack);
   };
 
   // Internal recursive comparison function for `isEqual`.
   deepEq = function(a, b, aStack, bStack) {
     // Unwrap any wrapped objects.
     if (a instanceof _) a = a._wrapped;
     if (b instanceof _) b = b._wrapped;
     // Compare `[[Class]]` names.
     var className = toString.call(a);
     if (className !== toString.call(b)) return false;
     switch (className) {
       // Strings, numbers, regular expressions, dates, and booleans are compared by value.
       case '[object RegExp]':
       // RegExps are coerced to strings for comparison (Note: '' + /a/i === '/a/i')
       case '[object String]':
         // Primitives and their corresponding object wrappers are equivalent; thus, `"5"` is
         // equivalent to `new String("5")`.
         return '' + a === '' + b;
       case '[object Number]':
         // `NaN`s are equivalent, but non-reflexive.
         // Object(NaN) is equivalent to NaN.
         if (+a !== +a) return +b !== +b;
         // An `egal` comparison is performed for other numeric values.
         return +a === 0 ? 1 / +a === 1 / b : +a === +b;
       case '[object Date]':
       case '[object Boolean]':
         // Coerce dates and booleans to numeric primitive values. Dates are compared by their
         // millisecond representations. Note that invalid dates with millisecond representations
         // of `NaN` are not equivalent.
         return +a === +b;
       case '[object Symbol]':
         return SymbolProto.valueOf.call(a) === SymbolProto.valueOf.call(b);
     }
 
     var areArrays = className === '[object Array]';
     if (!areArrays) {
       if (typeof a != 'object' || typeof b != 'object') return false;
 
       // Objects with different constructors are not equivalent, but `Object`s or `Array`s
       // from different frames are.
       var aCtor = a.constructor, bCtor = b.constructor;
       if (aCtor !== bCtor && !(_.isFunction(aCtor) && aCtor instanceof aCtor &&
                                _.isFunction(bCtor) && bCtor instanceof bCtor)
                           && ('constructor' in a && 'constructor' in b)) {
         return false;
       }
     }
     // Assume equality for cyclic structures. The algorithm for detecting cyclic
     // structures is adapted from ES 5.1 section 15.12.3, abstract operation `JO`.
 
     // Initializing stack of traversed objects.
     // It's done here since we only need them for objects and arrays comparison.
     aStack = aStack || [];
     bStack = bStack || [];
     var length = aStack.length;
     while (length--) {
       // Linear search. Performance is inversely proportional to the number of
       // unique nested structures.
       if (aStack[length] === a) return bStack[length] === b;
     }
 
     // Add the first object to the stack of traversed objects.
     aStack.push(a);
     bStack.push(b);
 
     // Recursively compare objects and arrays.
     if (areArrays) {
       // Compare array lengths to determine if a deep comparison is necessary.
       length = a.length;
       if (length !== b.length) return false;
       // Deep compare the contents, ignoring non-numeric properties.
       while (length--) {
         if (!eq(a[length], b[length], aStack, bStack)) return false;
       }
     } else {
       // Deep compare objects.
       var keys = _.keys(a), key;
       length = keys.length;
       // Ensure that both objects contain the same number of properties before comparing deep equality.
       if (_.keys(b).length !== length) return false;
       while (length--) {
         // Deep compare each member
         key = keys[length];
         if (!(has(b, key) && eq(a[key], b[key], aStack, bStack))) return false;
       }
     }
     // Remove the first object from the stack of traversed objects.
     aStack.pop();
     bStack.pop();
     return true;
   };
 
   // Perform a deep comparison to check if two objects are equal.
   _.isEqual = function(a, b) {
     return eq(a, b);
   };
 
   // Is a given array, string, or object empty?
   // An "empty" object has no enumerable own-properties.
   _.isEmpty = function(obj) {
     if (obj == null) return true;
     if (isArrayLike(obj) && (_.isArray(obj) || _.isString(obj) || _.isArguments(obj))) return obj.length === 0;
     return _.keys(obj).length === 0;
   };
 
   // Is a given value a DOM element?
   _.isElement = function(obj) {
     return !!(obj && obj.nodeType === 1);
   };
 
   // Is a given value an array?
   // Delegates to ECMA5's native Array.isArray
   _.isArray = nativeIsArray || function(obj) {
     return toString.call(obj) === '[object Array]';
   };
 
   // Is a given variable an object?
   _.isObject = function(obj) {
     var type = typeof obj;
     return type === 'function' || type === 'object' && !!obj;
   };
 
   // Add some isType methods: isArguments, isFunction, isString, isNumber, isDate, isRegExp, isError, isMap, isWeakMap, isSet, isWeakSet.
   _.each(['Arguments', 'Function', 'String', 'Number', 'Date', 'RegExp', 'Error', 'Symbol', 'Map', 'WeakMap', 'Set', 'WeakSet'], function(name) {
     _['is' + name] = function(obj) {
       return toString.call(obj) === '[object ' + name + ']';
     };
   });
 
   // Define a fallback version of the method in browsers (ahem, IE < 9), where
   // there isn't any inspectable "Arguments" type.
   if (!_.isArguments(arguments)) {
     _.isArguments = function(obj) {
       return has(obj, 'callee');
     };
   }
 
   // Optimize `isFunction` if appropriate. Work around some typeof bugs in old v8,
   // IE 11 (#1621), Safari 8 (#1929), and PhantomJS (#2236).
   var nodelist = root.document && root.document.childNodes;
   if (typeof /./ != 'function' && typeof Int8Array != 'object' && typeof nodelist != 'function') {
     _.isFunction = function(obj) {
       return typeof obj == 'function' || false;
     };
   }
 
   // Is a given object a finite number?
   _.isFinite = function(obj) {
     return !_.isSymbol(obj) && isFinite(obj) && !isNaN(parseFloat(obj));
   };
 
   // Is the given value `NaN`?
   _.isNaN = function(obj) {
     return _.isNumber(obj) && isNaN(obj);
   };
 
   // Is a given value a boolean?
   _.isBoolean = function(obj) {
     return obj === true || obj === false || toString.call(obj) === '[object Boolean]';
   };
 
   // Is a given value equal to null?
   _.isNull = function(obj) {
     return obj === null;
   };
 
   // Is a given variable undefined?
   _.isUndefined = function(obj) {
     return obj === void 0;
   };
 
   // Shortcut function for checking if an object has a given property directly
   // on itself (in other words, not on a prototype).
   _.has = function(obj, path) {
     if (!_.isArray(path)) {
       return has(obj, path);
     }
     var length = path.length;
     for (var i = 0; i < length; i++) {
       var key = path[i];
       if (obj == null || !hasOwnProperty.call(obj, key)) {
         return false;
       }
       obj = obj[key];
     }
     return !!length;
   };
 
   // Utility Functions
   // -----------------
 
   // Run Underscore.js in *noConflict* mode, returning the `_` variable to its
   // previous owner. Returns a reference to the Underscore object.
   _.noConflict = function() {
     root._ = previousUnderscore;
     return this;
   };
 
   // Keep the identity function around for default iteratees.
   _.identity = function(value) {
     return value;
   };
 
   // Predicate-generating functions. Often useful outside of Underscore.
   _.constant = function(value) {
     return function() {
       return value;
     };
   };
 
   _.noop = function(){};
 
   // Creates a function that, when passed an object, will traverse that object’s
   // properties down the given `path`, specified as an array of keys or indexes.
   _.property = function(path) {
     if (!_.isArray(path)) {
       return shallowProperty(path);
     }
     return function(obj) {
       return deepGet(obj, path);
     };
   };
 
   // Generates a function for a given object that returns a given property.
   _.propertyOf = function(obj) {
     if (obj == null) {
       return function(){};
     }
     return function(path) {
       return !_.isArray(path) ? obj[path] : deepGet(obj, path);
     };
   };
 
   // Returns a predicate for checking whether an object has a given set of
   // `key:value` pairs.
   _.matcher = _.matches = function(attrs) {
     attrs = _.extendOwn({}, attrs);
     return function(obj) {
       return _.isMatch(obj, attrs);
     };
   };
 
   // Run a function **n** times.
   _.times = function(n, iteratee, context) {
     var accum = Array(Math.max(0, n));
     iteratee = optimizeCb(iteratee, context, 1);
     for (var i = 0; i < n; i++) accum[i] = iteratee(i);
     return accum;
   };
 
   // Return a random integer between min and max (inclusive).
   _.random = function(min, max) {
     if (max == null) {
       max = min;
       min = 0;
     }
     return min + Math.floor(Math.random() * (max - min + 1));
   };
 
   // A (possibly faster) way to get the current timestamp as an integer.
   _.now = Date.now || function() {
     return new Date().getTime();
   };
 
   // List of HTML entities for escaping.
   var escapeMap = {
     '&': '&amp;',
     '<': '&lt;',
     '>': '&gt;',
     '"': '&quot;',
     "'": '&#x27;',
     '`': '&#x60;'
   };
   var unescapeMap = _.invert(escapeMap);
 
   // Functions for escaping and unescaping strings to/from HTML interpolation.
   var createEscaper = function(map) {
     var escaper = function(match) {
       return map[match];
     };
     // Regexes for identifying a key that needs to be escaped.
     var source = '(?:' + _.keys(map).join('|') + ')';
     var testRegexp = RegExp(source);
     var replaceRegexp = RegExp(source, 'g');
     return function(string) {
       string = string == null ? '' : '' + string;
       return testRegexp.test(string) ? string.replace(replaceRegexp, escaper) : string;
     };
   };
   _.escape = createEscaper(escapeMap);
   _.unescape = createEscaper(unescapeMap);
 
   // Traverses the children of `obj` along `path`. If a child is a function, it
   // is invoked with its parent as context. Returns the value of the final
   // child, or `fallback` if any child is undefined.
   _.result = function(obj, path, fallback) {
     if (!_.isArray(path)) path = [path];
     var length = path.length;
     if (!length) {
       return _.isFunction(fallback) ? fallback.call(obj) : fallback;
     }
     for (var i = 0; i < length; i++) {
       var prop = obj == null ? void 0 : obj[path[i]];
       if (prop === void 0) {
         prop = fallback;
         i = length; // Ensure we don't continue iterating.
       }
       obj = _.isFunction(prop) ? prop.call(obj) : prop;
     }
     return obj;
   };
 
   // Generate a unique integer id (unique within the entire client session).
   // Useful for temporary DOM ids.
   var idCounter = 0;
   _.uniqueId = function(prefix) {
     var id = ++idCounter + '';
     return prefix ? prefix + id : id;
   };
 
   // By default, Underscore uses ERB-style template delimiters, change the
   // following template settings to use alternative delimiters.
   _.templateSettings = {
     evaluate: /<%([\s\S]+?)%>/g,
     interpolate: /<%=([\s\S]+?)%>/g,
     escape: /<%-([\s\S]+?)%>/g
   };
 
   // When customizing `templateSettings`, if you don't want to define an
   // interpolation, evaluation or escaping regex, we need one that is
   // guaranteed not to match.
   var noMatch = /(.)^/;
 
   // Certain characters need to be escaped so that they can be put into a
   // string literal.
   var escapes = {
     "'": "'",
     '\\': '\\',
     '\r': 'r',
     '\n': 'n',
     '\u2028': 'u2028',
     '\u2029': 'u2029'
   };
 
   var escapeRegExp = /\\|'|\r|\n|\u2028|\u2029/g;
 
   var escapeChar = function(match) {
     return '\\' + escapes[match];
   };
 
   // JavaScript micro-templating, similar to John Resig's implementation.
   // Underscore templating handles arbitrary delimiters, preserves whitespace,
   // and correctly escapes quotes within interpolated code.
   // NB: `oldSettings` only exists for backwards compatibility.
   _.template = function(text, settings, oldSettings) {
     if (!settings && oldSettings) settings = oldSettings;
     settings = _.defaults({}, settings, _.templateSettings);
 
     // Combine delimiters into one regular expression via alternation.
     var matcher = RegExp([
       (settings.escape || noMatch).source,
       (settings.interpolate || noMatch).source,
       (settings.evaluate || noMatch).source
     ].join('|') + '|$', 'g');
 
     // Compile the template source, escaping string literals appropriately.
     var index = 0;
     var source = "__p+='";
     text.replace(matcher, function(match, escape, interpolate, evaluate, offset) {
       source += text.slice(index, offset).replace(escapeRegExp, escapeChar);
       index = offset + match.length;
 
       if (escape) {
         source += "'+\n((__t=(" + escape + "))==null?'':_.escape(__t))+\n'";
       } else if (interpolate) {
         source += "'+\n((__t=(" + interpolate + "))==null?'':__t)+\n'";
       } else if (evaluate) {
         source += "';\n" + evaluate + "\n__p+='";
       }
 
       // Adobe VMs need the match returned to produce the correct offset.
       return match;
     });
     source += "';\n";
 
     // If a variable is not specified, place data values in local scope.
     if (!settings.variable) source = 'with(obj||{}){\n' + source + '}\n';
 
     source = "var __t,__p='',__j=Array.prototype.join," +
       "print=function(){__p+=__j.call(arguments,'');};\n" +
       source + 'return __p;\n';
 
     var render;
     try {
       render = new Function(settings.variable || 'obj', '_', source);
     } catch (e) {
       e.source = source;
       throw e;
     }
 
     var template = function(data) {
       return render.call(this, data, _);
     };
 
     // Provide the compiled source as a convenience for precompilation.
     var argument = settings.variable || 'obj';
     template.source = 'function(' + argument + '){\n' + source + '}';
 
     return template;
   };
 
   // Add a "chain" function. Start chaining a wrapped Underscore object.
   _.chain = function(obj) {
     var instance = _(obj);
     instance._chain = true;
     return instance;
   };
 
   // OOP
   // ---------------
   // If Underscore is called as a function, it returns a wrapped object that
   // can be used OO-style. This wrapper holds altered versions of all the
   // underscore functions. Wrapped objects may be chained.
 
   // Helper function to continue chaining intermediate results.
   var chainResult = function(instance, obj) {
     return instance._chain ? _(obj).chain() : obj;
   };
 
   // Add your own custom functions to the Underscore object.
   _.mixin = function(obj) {
     _.each(_.functions(obj), function(name) {
       var func = _[name] = obj[name];
       _.prototype[name] = function() {
         var args = [this._wrapped];
         push.apply(args, arguments);
         return chainResult(this, func.apply(_, args));
       };
     });
     return _;
   };
 
   // Add all of the Underscore functions to the wrapper object.
   _.mixin(_);
 
   // Add all mutator Array functions to the wrapper.
   _.each(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(name) {
     var method = ArrayProto[name];
     _.prototype[name] = function() {
       var obj = this._wrapped;
       method.apply(obj, arguments);
       if ((name === 'shift' || name === 'splice') && obj.length === 0) delete obj[0];
       return chainResult(this, obj);
     };
   });
 
   // Add all accessor Array functions to the wrapper.
   _.each(['concat', 'join', 'slice'], function(name) {
     var method = ArrayProto[name];
     _.prototype[name] = function() {
       return chainResult(this, method.apply(this._wrapped, arguments));
     };
   });
 
   // Extracts the result from a wrapped and chained object.
   _.prototype.value = function() {
     return this._wrapped;
   };
 
   // Provide unwrapping proxy for some methods used in engine operations
   // such as arithmetic and JSON stringification.
   _.prototype.valueOf = _.prototype.toJSON = _.prototype.value;
 
   _.prototype.toString = function() {
     return String(this._wrapped);
   };
 
   // AMD registration happens at the end for compatibility with AMD loaders
   // that may not enforce next-turn semantics on modules. Even though general
   // practice for AMD registration is to be anonymous, underscore registers
   // as a named module because, like jQuery, it is a base library that is
   // popular enough to be bundled in a third party lib, but not be part of
   // an AMD load request. Those cases could generate an error when an
   // anonymous define() is called outside of a loader request.
   if (typeof define == 'function' && define.amd) {
     define('underscore', [], function() {
       return _;
     });
   }
 }());